Vapor generators



April 7, 1964 R. H. EVANS VAPOR GENERATORS Filed July 27, 1960 F/GI.

Inventor Ram/m0 H may ElvANs Attorney United States Patent Ofiice 3,127,875 Patented Apr. 7, 1964 3,127,375 VALPGR GENERATQRS Richard Henry Evans, Surrey, Eugiand, assignor to liabcucir ti: Wiicon, Limited, London, Engiand, a corporation of Great Britain Fiied July 27, rues, Ser. No. 45,619 3 Claims. (Cl. 122-235} This invention relates to vapor generators having wall tubes arranged to operate with forced flow of the working medium therethrough. Such tubes are found, for example, in the superheater of a natural circulation boiler, tubes of which line a furnace chamber wall area, or in a forced flow, once-through boiler with tubes lining the furnace chamber walls.

More particularly, the invention is related to a forced flow tubulous boiler having circuits connected in parallel for flow of working medium and an upright furnace chamber space with walls lined by tube lengths of the circuits wherein the tubulous lining has sections extending over respective zones one above the other and each formed by horizontal or substantially horizontal tube lengths of the respective circuits, the tube lengths of the circuits being distributed in the zones in a manner adapted to give approximately equal heat inputs to the circuits.

In a vapor generator with furnace chamber wall tubes it is important that the tubes shall be drainable but the difficulty arises that, if the tubes are horizontal or substantially horizontal, the mode of lateral tube displacement at necessary apertures in the Wall normally employed with vertical wall tubes cannot be used since slugs of liquid, which cannot be drained, result.

The present invention comprises a vapor generator with heat exchange surfaces including drainable wall tubes arranged to operate with forced flow of the working medium therethrough having horizontal or substantially horizontal tube lengths lining an area of furnace wall and including, at an aperture in the wall, tube portions displaced laterally in an outward horizontal or substantially horizontal direction.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

FIGURE 1 is a sectional side elevation, taken along the line 11 of FIG. 2 of a number of horizontal wall tubes arranged to provide a sight aperture, insulating material being omitted for the sake of clarity;

FIGURE 2 is a front elevation of a door closing the sight aperture; and

FIGURE 3 is a sectional plan view taken on the line 3-3 of FIGURE 1.

Referring to the drawings there are shown portions of a wall of a tubulous boiler, the insulating material and support means being omitted for the sake of clarity, the apertures being disposed in the upper parts of the furnace chamber of a forced fiow type boiler.

Referring now to the drawings, a sight aperture 32 in the wall is formed partly by bending tubes of upper and lower tube groups C and D horizontally to offset portions E and F of the tubes, and partly by bending alternate tubes of a tube group G intermediate the groups C and D horizontally to offset portions H of the tubes.

Thus each tube 34 of the upper group C includes limbs 36, 38, bent at an acute angle to converge in a direction away from the furnace chamber, and a portion 4t) connecting the limbs 36, 38. Webs or fillets 39 welded intermediate the tubes are similarly bent. The portion 40A of the uppermost tube 34A of the group C is offset only a small distance from the remaining tubes of the wall and successive tube portions 46 5, MC of the group C are ofiset outwardly progressively to greater extents to provide, together with the adjacent portions of the webs 39, an inwardly flaring upper boundary flanking the aperture 32.

Tubes of the lower group D are bent in a similar manner to provide, together with the adjacent portions of the webs 39, an inwardly flaring lower boundary flanking the aperture 32. Studs (not shown) are provided on the outer sides of the tube portions F to support insulating material.

Each alternate tube 44 of the intermediate tube group G inciudes limbs 46, 48 bent at an acute angle to converge in a direction away from the furnace chamber and a portion 5% connecting the limbs 46, 48. No bends are made in the remaining tubes 52 of the tube group G. The webs 39 intermediate the tubes of the group G terminate adjacent the offset portions H of the tubes. Plates 54 are welded intermediate adjacent limbs 46 and adjacent limbs 48 of the alternate tubes 44 and are welded at the inner edges 5s to the intervening tubes 52 and the adjacent webs 39. At the outer edges 58 the plates are welded to side members 66 of a framework 62, the upper and lower members 64 of which are respectively welded to the lowermost portion 46C of the upper tube group C and the corresponding uppermost tube 49D of the lower tube group D. Thus the limbs 46, 48 together with the plates 54 provide inwardly flaring lateral boundaries flanking the aperture 32.

The framework @223 supports a door d5 lined with insulating material as by means of a yoke 63 mounted at one end by a hinge "/ii on a bracket '72 secured to one of the side members of the framework 62. The other end of the yoke as is secured, in the closed position, by a pin "74% passing through lugs '76 mounted on a bracket secured to the other of the side members 69 of the framework as. A central, closing pressure is exerted on the door by means of a handwheel 8t provided with a threaded shank 82 coacting with a threaded hole 84 in the yoke 63 and a collar as bearing against the door 65.

To open the door 65, the closing pressure exerted through the handwheel shank 32 is released, the pin 74 withdrawn and the door swung to the open position.

It will be appreciated that since the alternate tubes 44 of the intermediate tube group G are displaced outwardly it is possible to see into the furnace chamber through the gaps between the tubes of the group G which are displaced and the tubes of the group G which are not displaced and between the tubes of the group G and the offset tube portions E and F at the top and at the bottom of the aperture.

It will be appreciated that, since the displacement of the laterally displaced tube portions in each of the applications described above is horizontal or substantially horizontal, that is to say in a vertical wall the displacements are normal or substantially normal to the wall, the whole of each tube is drainable.

While in accordance with the provisions of the statutes 1 have illustrated and described herein the best form and mode of operation of the invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

1. in combination with a planar wall portion including contiguous coplanar horizontally extending drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough and providing a boundary for a chamber confining high temperature heating gases, means forming an aperture in said wall, means forming a pocket flanking said aperture and having an access opening disposed directly opposite said aperture, and a door normally closing said access opening, said last named means comprising intermediate portions of alternate tubes of a group of said tube lengths displaced lateraliy from said wall in an outward direction, and intermediate portions of the remaining tubes of said group extending horizontally in the plane of said wall and across said aperture to screen said door from the heating gases, each of said intermediate displaced tube portions having its entire length disposed in a plane extending normal to the plane of said wall.

2. In combination with a planar wall portion including contiguous coplanar horizontally extending drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough and providing a boundary for a chamber confining high temperature heating gases, means forming an aperture in said wall, means forming a pocket flanking said aperture and having an access opening disposed directly opposite said aperture, and a door normally closing said access opening, said last named means comprising intermediate portions of alternate tubes of a group of said tube lengths displaced laterally' from said wall in an outward direction, and intermediate portions of the remaining tubes of said group extending horizontally in the plane of said wall and across said aperture to screen said door from the heating gases, each of said intermediate displaced tube portions having its entire length disposed in a plane extending normal to the plane of said wall, said pocket being of gradually decreasing cross-sectional area throughout its extent in the direction of said access opening in planes extending parallel to the plane of said wall.

3. In combination with a planar wall portion including a vertical row of contiguous coplanar horizontally extending drainable fluid cooled tube lengths arranged for parallel flow of fluid therethrough and providing a boundary for a chamber confining high temperature heating gases, means forming an aperture in said wall, means forming an inwardly flaring pocket flanking said aperture and having an access opening disposed directly opposite said aperture, and a door normally closing said access opening, said last named means comprising intermediate portions of alternate tubes of a group of said tube lengths displaced laterally from said wall in an outward substantially horizontal direction, and intermediate portions of the remaining tubes of said group extending horizontally in the plane of said wall and across said aperture to screen said door from the heating gases, each of said intermediate displaced tube portions having its entire length disposed in a plane extending normal to the plane of said wall, said pocket being of gradually decreasing cross-sectional area throughout its extent in the direction of said access opening in planes extending parallel to the plane of said wall.

References Cited in the tile of this patent UNITED STATES PATENTS Mayo Mar. 19, 1935 Kerr et a1 Sept. 5, 1944 OTHER REFERENCES 

1. IN COMBINATION WITH A PLANAR WALL PORTION INCLUDING CONTIGUOUS COPLANAR HORIZONTALLY EXTENDING DRAINABLE FLUID COOLED TUBE LENGTHS ARRANGED FOR PARALLEL FLOW OF FLUID THERETHROUGH AND PROVIDING A BOUNDARY FOR A CHAMBER CONFINING HIGH TEMPERATURE HEATING GASES, MEANS FORMING AN APERTURE IN SAID WALL, MEANS FORMING A POCKET FLANKING SAID APERTURE AND HAVING AN ACCESS OPENING DISPOSED DIRECTLY OPPOSITE SAID APERTURE, AND A DOOR NORMALLY CLOSING SAID ACCESS OPENING, SAID LAST NAMED MEANS COMPRISING INTERMEDIATE PORTIONS OF ALTERNATE TUBES OF A GROUP OF SAID TUBE LENGTHS DISPLACED LATERALLY FROM SAID WALL IN AN OUTWARD DIRECTION, AND INTERMEDIATE PORTIONS OF THE REMAINING TUBES OF SAID GROUP EXTENDING HORIZONTALLY IN THE PLANE OF SAID WALL AND ACROSS SAID APERTURE TO SCREEN SAID DOOR FROM THE HEATING GASES, EACH OF SAID INTERMEDIATE DISPLACED TUBE PORTIONS HAVING ITS ENTIRE LENGTH DISPOSED IN A PLANE EXTENDING NORMAL TO THE PLANE OF SAID WALL. 